This invention lies in the field of ski lift and equivalent transport apparatus and is directed to means for preventing vehicle carrying ropes from being dislodged and falling from the rope-support assemblies. It is more particularly directed toward apparatus for guarding the margins of sheaves to prevent dislodgement of the ropes while not interfering with normal operation of the total apparatus.
In conventional ski lifts, a series of towers is provided along with turnaround stations at each end of a route segment. Arms extend out to each side of each tower and pivotally carry bogey beams which in turn carry sheaves. An endless cable, or rope, extends around the bull wheel at each turnaround station and rides in the grooves of the sheaves supported by the towers. The passenger carrying vehicles are usually supported by a generally vertical hanger bar having at its upper end a transversely extending hanger arm, the free end of which is fixedly attached to a selected point on the rope.
The hanger arm and its attachment to the rope constitute enlargements on the rope which set up a disturbance when they strike a sheave. Operation of the power plant may cause vibration in the rope, and wind action on the vehicles and rope often causes both vertical and horizontal fluctuations. When these actions happen to combine in certain ways the disturbance can be sufficient to dislodge the rope from the supporting sheaves and let it drop to the ground.
Various schemes have been proposed and put into practice for overcoming this difficulty. Some have been satisfactory but were complicated and expensive or difficult to apply to existing installations. Others were simple but not very satisfactory. One type simply provides a shelf or bracket beside a pair of supporting sheaves which may catch the rope if it falls from the sheaves. Another provides a bracket extending logitudinally above the sheaves and carrying a series of rollers which contact the rope and tend to hold it in the sheaves. Another has a series of arms carried by supports rotating on a vertical axis, the arms underlying the rope and and being displaced by contact with the hanger bar. Another type of apparatus used stationary rope hung from the supports by short cables and the vehicle has motive power to cause it to move along the rope. Its supporting wheels are disk-like and overlie the cable from opposite sides being formed with radial arms to pass the supporting cables for the rope.